A substrate or a plurality of substrates, for example wafers or other plate-shaped substrates, can in general be held by means of a substrate carrier for example during a coating process (or any other processes for treating substrates). The substrate carrier herein can be utilized for holding the substrate or the substrates at a predefined position in a coating chamber, for example, or for transporting said substrate or substrates though a coating chamber, and/or for moving said substrate or substrates in the coating chamber. Substrate carriers in which substrates are placed in only a loose manner are conventionally used, for example, wherein the substrates in this case can easily fall out of the substrate carrier, for example by virtue of the air that is admitted when a vacuum chamber is being ventilated. Therefore, conventional substrate carriers can have a cover element, which rests on the substrate and weighs down the latter, or presses the substrate onto the substrate carrier, respectively. Alternatively, wafers are jammed between two flexible structures (for example between two rubber rings) and thus fixed in a mounting, for example.
Mechanical fixing between the substrate carrier and the substrates or the supporting surfaces for the substrates, respectively, can generate mechanical stress which can damage the substrates. For example, even minor deformations of the supporting surfaces can lead to punctiform stress on the substrate resting thereon, and/or to parasitic coating of those portions of the substrate that do not fully rest thereon (insufficient sputtering).
Substrate carriers are conventionally used in conjunction with coating installations which enable the coating of one side of substrates that are held beside one another (that is to say the front side of said substrates). Should coating of the reverse side be required, the substrates are turned over and again processed on one side only, even when identical or dissimilar coating of the reverse side is performed, for example. Alternatively, substrate carriers are used in conjunction with coating installations which enable the coating of both sides of substrates that are held beside one another (that is to say the front and the reverse side of said substrates).
However, should only one-sided coating be performed (that is to say that illustratively only the front side of substrates are coated) in a coating installation which is conceived for coating both sides of a substrate tier, the processing capacity of the coating installation is halved, this compromising the economy of said coating installation.